🚀 go-pugleaf

In article <3581@caslon.cs.arizona.edu> huber@cs.arizona.edu (Eric N. Huber) writes:
>	Now the question comes of do these virtual particles really exist, or
>like i, are they just a figment of our imagination?  The usual experiment I've
>heard of involves a free electrical charge in space.  If virtual particles 
>exist, they should be popping into existance around the electron in the form
>of virtual positrons.  These virtual positive charges will 'shield' the
>electron's charge, and the drop may be measured.  Neat trick!

This test has been made in numerous contexts. Perhaps the most well-known
is that this is simply the vacuum-polarization term in the Lamb shift.
To oversimplify greatly, the e+e- pairs ``popping into and out of existence''
near the nucleus of a hydrogen atom perturb the energy levels of the electron
by screening the nuclear charge. This effect has been measured and is in good
agreement with theory. Similar effects abound in other areas of physics.

It's important to note, though, that all you can do is measure energy levels
and compare them with theory. You can't turn off this phenomenon and compare
results with and without the virtual particles.

---Jon